Grinding or abrading machine



April 8, 1930. H. H. AsBRlDGE GRIND`ING OR ABRADING MACHINE Filed March 14, 1929 r/l/ fig/114.4114 Il Patented Apr. 8, 193i@ UNITED STATES rArENr OFFICE HARRY HALES ASBRIDGE, CF ASHTON-ON-MERSEY, ENG-LAND, ASSIGNOR T0 THE CHURCHILL MACHINE TOCL COMPANY LIMITED, OF BROADHEATH, NEAR MAN- CHESTER, ENGLAND, A. BRITISH COMPANY I GRINDING OR ABRAIDING: MACHINE Application led March 14, 1929, Serial No. 34"?,90, and in Great Britain April 24, 192B.

This invention relates to grinding or abrading machines, and has for its object the provision of improved mechanism for the feeding of the grinding wheel to the work piece,

5 the feeding mechanism being of the type employing a face cam engaging' a projection on the slide carrying the grinding wheel or disc, the cam being rotated by ratchet mechanism.

` The invention, which is particularly applicable to machines for internal grinding operations, comprises the arrangement of the cam engaging the slide carrying the grinding wheel or disc and the operating ratchet of said cam, so that the feeding movement resulting from each cycle or revolution of the cam is made in separate and distinct stages, respectively adapted for a coarse or roughing feed and a fine or finishing feed.

Referring to the accompanying explanatory drawings Figure 1 is a sectional elevation showing a sufficient portion of a grinding machine to illustrate the application of the invention.

Figure 2 is an end view showing the ratchet wheel and some associated parts of the feeding mechanism.

Figure 3 is a straight line development of the helical operating face of the cam.

Like reference letters in the different views indicate like parts.

The slide a carrying grinding wheel b contact-s through pin c with the cam d, the latter being a helical face cam and having intermittent rotary movements imparted thereto through mechanism including a ratchet wheel e.

In accordance with this invention, the said face cam 0l is provided with a plurality of gaps or recesses (indicated at Z1 and (Z2 in the straight line development of the cam shown at Figure 3) into which the said pin c retreats (under the influence of the slide weight ,f or a spring) when each gap in its turn is brought into alignment with the pin on each. revolution of the cam. A plurality of gaps e1 and e2 are also provided in the periphery of the ratchet wheel e.

At the commencement of each forward or feed movement to be given to the slide a, hy the cam d (against the action of the weight 7 or was operating. Atthe same time, the gap e1 in the ratchet wheel e will have arrived in a position under the tip of the pawl g so that the latter will work idly in said gap and the intermittent rotary movement of the ratchet "-f wheel is arrested.

The aforesaid stage of t-he feed movement provides for the coarse or rough grinding of the work piece and the automatic withdrawal of the grinding` disc at the end of the stage interval can be utilized to true up the said disc or prepare it for the second or fine or iinislf. grinding stage represented by the movement of the cam in contact with pin c progressing from the said gap d1 to the gap cl2 which is 7 deeper than Z1 and permits of a further retreat of the grinding disc to facilitate manipulation or removal of the work piece at the end of the grinding` cycle represented by a complete revolution of the cam (Z.

To start the second stage grindingI the ratchet wheel is given a small rotary movement by hand to carry the gap el clear of the pawl g.

A screw and nut device as 7i. and t' or any equivalent and ordinary means are employed for the axial adjustment of the cam l to compensate for wear of the grinding disc and to suit the diameter thereof.

rlhe circles shown in Figure 3 indicate the progressive positions of contact between the pin c of slide a, and the cam surface during a complete cycle or revolution of the cam.

What I claim is l. ln the feeding mechanism of grinding a plurality of gaps or recesses in its operative face keyed to said spindle, a ratchet wheel also secured upon said spindle with gaps therein corresponding with the gaps in the cam, a pavvl imparting intermittent move- 5 ments to said ratchet Wheel and cam except when it enters the gaps in the ratchet Wheel,

g and means upon said slide engaging said cam so that the slide has .ieedmovements imparted to it by said cam. Y

10 2. In the feeding mechanism of grinding machines claimed in claim l, meansfor traversing the cam axially along its SpindleV In `testimony whereof I have signed my name to this specification.

15 HARRY HALES ASBRIDGE. 

